My idea was to have the bullets as long as possible but to still work in the mag without jamming and gradually push them back to get best accuracy for mine this was on the money at 2.273", doesn't leave much gap in the mag, but iv'e had no problems, ie 10mm group's at 100 yds with the Drone Pro with the day light filter on, and in fairness you carn't see to that level after all it is a night vision.